MICROPATTERNED COMPONENT AND METHOD FOR MANUFACTURING A MICROPATTERNED COMPONENT
A micropatterned component, for measuring accelerations and/or yaw rates, including a substrate having a principal plane of extension of the substrate, an electrode, and a further electrode; the electrode having a principal plane of extension of the electrode, and the further electrode having a principal plane of extension of the further electrode; the principal plane of extension of the electrode being set parallelly to a normal direction perpendicular to the principal plane of extension of the substrate; the principal plane of extension of the further electrode being set parallelly to the normal direction; the electrode having an electrode height extending in the normal direction; the electrode having a flow channel extending completely through the electrode in a direction parallel to the principal plane of extension of the substrate; the flow channel having a channel depth extending parallelly to the normal direction; the channel depth being less than the electrode height.
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The present application claims priority to and the benefit of German patent application no. 10 2013 208 825.6, which was filed in Germany on May 14, 2013, the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention is based on a micropatterned component.
BACKGROUND INFORMATIONSuch micropatterned components are believed to be generally understood. For example, micropatterned components in the form of micromechanical inertial sensors are mass-produced for measuring accelerations and yaw rates for different applications in the automotive branch and/or in the sale of consumer goods. The inertial sensors normally include electrode set-ups for detecting a change in capacitance, the change in capacitance being a measure of an inertial force acting upon an inertial mass of the inertial sensor. For example, an inertial force may be an accelerative force and/or a Coriolis force of an acceleration sensor and/or of a yaw-rate sensor. The electrode set-up may include, for example, two plate electrodes having respective principal electrode planes of extension positioned in parallel with each other; one of the plate electrodes being able to be excited into a vibration along a vibration direction perpendicular to a principal plane of extension of the electrode. In this connection, the vibration direction may be set, for example, parallelly to a principal plane of extension of a substrate of the micropatterned component.
The electrode set-up is normally situated in a hermetically sealed cavity or hollow space of the micropatterned component; a comparatively lower cavity pressure prevailing in the cavity. With increasing layer thickness or electrode height along a normal direction perpendicular to the principal plane of extension of the substrate, edge flow effects and damping effects, for instance, the so-called squeeze-film damping, have a negative effect on the efficiency, signal noise and/or offset.
SUMMARY OF THE INVENTIONThus, an object of the present invention is to provide a micropatterned component and a method for manufacturing a micropatterned component, where in the case of a given cavity pressure, damping forces in the electrode set-up are reduced in comparison with the related art and the mechanical efficiency is increased, and/or the electrical sensitivity of the electrode set-up is improved without increasing the damping forces.
In comparison with the related art, the micropatterned component of the present invention and the method of the present invention for manufacturing a micropatterned component according to the alternative independent claims have the advantage that, due to the introduction of one or more flow channels, which each extend completely through the electrode taking the form of, in particular, a plate electrode, in a direction parallel to the principal plane of extension of the substrate and/or perpendicular to the principal plane of extension of the electrode, gas molecules emerging in response to the occurrence of the squeeze-film damping may escape through the flow channels, which means that damping forces acting upon the electrodes are considerably reduced in comparison with electrodes without a flow channel. The forming of the flow channels of the electrode advantageously causes the sensitivity of the electrode set-up, which is also referred to below as a capacitor set-up, to decrease only slightly. A portion of the missing capacitor area is particularly advantageously compensated for by stray-field components from the lateral surfaces of the slotted electrode or electrode having the flow channel. Consequently, the sensitivity of the electrode set-up with regard to the detection of the change in capacitance is improved by increasing the electrode height; the damping effects only increasing slightly or not at all with increasing electrode height. It particular may be the case for the flow channels, which are also referred to here as slots, to completely penetrate the electrode height of the electrode in a direction parallel to the principal plane of extension of the substrate, and in particular, perpendicular to the principal plane of extension of the electrode; in the case of at least two flow channels situated on the electrode, in particular, the channel spacing may be less than the electrode height or equal to the electrode height. The channel depth may extend over more than 50% of the electrode height along the normal direction. As an alternative to a channel depth smaller than the electrode height, the channel depth may be, in particular, equal to the electrode height.
Using a two-stage trenching process of the method according to the present invention, it is also advantageously possible to form a flow channel from the electrode without etching the electrode through the entire layer thickness of the functional layer or through the entire electrode height in the normal direction. In the second production step, during the first time interval, the electrode structure, which includes, in particular, the electrode, the further electrode and/or the inertial structure, is formed from the functional layer, up to a first structural depth. The structural depth, which is also referred to here as a depth of the first trench, is determined by the duration of the first time interval or the first instance of process control, which means that in this instance, there is no defined etch stop. In the third production step, the electrode structure is further etched, but now, the flow channels in the first electrode and/or further electrode additionally being formed or etched. In order to prevent the functional layer from being etched through completely, the third production step is brought to an end in a timely manner after the second time interval, and severe overetching is prevented.
Advantageous embodiments and developments of the present invention may be gathered from the dependent claims and the specification, with reference to the drawing.
According to a further refinement, the channel depth is between 60% and 95%, and may be between 70% and 90%, and particularly may be approximately 80% of the electrode height. In this manner, it is believed to be advantageously possible to form the electrode in one piece to have a comb structure, using the set-up of several flow channels; several tooth-shaped electrode segments, which are referred to as partial electrodes, are perpendicular to the vibration direction and parallel to the principal plane of extension of the substrate, and are spaced apart from one another by the flow channels, being interconnected in an electrically conductive manner. Alternatively, the partial electrodes may be situated, in particular, on a common carrier; the carrier being formed from a further functional layer, which is different from the functional layer from which the electrode is formed.
According to a further refinement, the electrode has a principal direction of extension of the electrode parallel to the principal plane of extension of the electrode and parallel to the principal plane of extension of the substrate; the electrode having several flow channels situated along the principal direction of extension of the electrode; the several flow channels having, in particular, a channel spacing; the channel spacing being, in particular, less than the electrode height. In this manner, it is advantageously possible to provide an improved flow path for the emerging gas molecules resulting from the squeeze-film damping. In particular, it is advantageously possible to provide a flow channel structure extending over all of the electrodes of the electrode set-up.
According to a further refinement, the electrode has a plurality of partial electrodes spaced apart from one another by the several flow channels; the partial electrodes being situated on a common carrier; the electrode being formed from, in particular, a functional layer; the carrier being formed from, in particular, a further functional layer connected to the functional layer. In this manner, it is advantageously possible to provide a space-saving electrode set-up of the micropatterned component that reduces damping forces.
According to a further refinement, the partial electrodes are interconnected in an electrically conductive manner via the carrier; the carrier being connected in an electrically conductive manner to a conducting element via, in particular, exactly one electrode contact element; the conducting element being situated on the substrate or in a further substrate connected to the substrate; the further substrate including, in particular, an integrated circuit. In this manner, it is advantageously possible to pattern the conducting element or the integrated circuit independently of the electrode set-up formed in the functional layer, and in particular, in the further functional layer. In particular, by attaching the partial electrodes to the further substrate including the one integrated circuit, it is advantageously possible to provide a wiring pattern, in order to position a plurality of partial electrodes, which have a comparatively small length, parallelly to the principal direction of extension of the electrode.
According to a further refinement, the electrode is fixed in position relative to the substrate; the further electrode being able to be displaced relative to the substrate, into a motion along a vibration direction; the vibration direction being set, in particular, parallel to the principal plane of extension of the substrate; the vibration direction being set, in particular, perpendicularly to the principal plane of extension of the electrode and/or to the principal plane of extension of the further electrode. In this manner, it is advantageously possible to form the moving electrodes and/or the fixed electrodes to have flow channels, so that the gas molecules from the squeeze-film damping are lead off particularly efficiently out of the gaps between the electrode and the further electrode.
According to a further refinement, the further electrode has the electrode height parallel to the normal direction; the further electrode having a further flow channel extending parallelly to the principal plane of extension of the substrate, completely through the further electrode; the further flow channel having a further channel depth extending parallelly to the normal direction; the further channel depth being less than the electrode height; in particular, the flow channel and the further flow channel being positioned one behind the other in series or side-by-side in a staggered manner, in a projection direction running along the vibration direction. In this manner, it is advantageously possible to reduce the squeeze-film damping forces and simultaneously provide a particularly sturdy and space-saving electrode set-up.
According to a further refinement of the method according to the present invention, in the second production step, the electrode is formed with a principal plane of extension of the electrode, and the further electrode is formed with a principal plane of extension of the further electrode, from the functional layer, as a function of the second patterning mask; the principal plane of extension of the electrode being set parallelly to the normal direction; the principal plane of extension of the further electrode being set parallelly to the normal direction; an electrode height extending in the normal direction being formed at the electrode. In this manner, it is advantageously possible to form the electrode structure to include the electrode, the further electrode, and/or the inertial structure, before the flow channels are positioned on the electrode and/or on the further electrode. This allows a comparatively simple and inexpensive manufacturing method to be provided, in order to be able to manufacture a multitude of micropatterned components simultaneously in a simple manner.
According to a further refinement of the method according to the present invention, in the third production step, a flow channel, which extends completely through the electrode in a direction parallel to the principal plane of extension of the substrate and has a channel depth extending parallelly to the normal direction, is formed from the electrode as a function of the first patterning mask; the channel depth being formed as a function of the second time interval, to be less than the electrode height. In this manner, in order to form the flow channels to have a channel depth less than the electrode height in the electrode and/or further electrode, it is advantageously possible to position a mask on the functional layer having a comparatively smooth upper surface parallel to the principal plane of extension of the substrate, by combining the first mask taking the form of, in particular, an oxide mask and the second mask taking the form of, in particular, a resist mask.
According to a further refinement of the method according to the present invention, in the third production step, the functional layer is provided with a functional layer thickness; in the fourth production step, the flow channel being formed to have the channel depth equal to the functional layer thickness. In particular, the functional layer is situated over a further functional layer in the normal direction, a patterning mask being situated between the further functional layer and the functional layer. In particular, the channel depth of the flow channel is determined by the position of the patterning mask between the functional layer and the further functional layer. In particular, the patterning mask is an etch stop mask, which limits the channel depth of the flow channel during the etching operation. In addition, In this manner, in particular, a plurality of partial electrodes are provided on a carrier formed from the further functional layer. The etch stop layer may be removed in a fifth production step.
Exemplary embodiments of the present invention are represented in the drawings and explained in more detail in the following description.
In the different figures, like parts are always denoted by the same reference symbols and are therefore usually labeled or mentioned only once.
A sectional view of a micropatterned component 1 according to a specific embodiment of the present invention is illustrated in
Inertial structure 40 is connected to a driving mechanism 42, in particular, by several, e.g., four, spring elements 43; driving mechanism 42 being anchored to substrate 10. In particular, driving mechanisms 42, spring elements 43 and/or inertial structure 40 are connected to a drive conducting element 20″ in an electrically conductive manner via a drive contact element 41. A further electrode 30″ may be situated on inertial structure 40, the further electrode being deflectable together with inertial structure 40.
In a central region, inertial structure 40 has an opening extending, in particular, parallel to principal plane of extension of the substrate 100; the opening being formed to be, in particular, rectangular, in order to surround a plurality of electrodes 30 and/or differential electrodes 30′. Further electrode 30″ may have a principal plane of extension of the further electrode 300″ (see, for example
Sectional views of different specific embodiments of an electrode 30, 30′, 30″ according to a specific embodiment of the present invention are represented in
A sectional view of a micropatterned component 1 according to a specific embodiment of the present invention is illustrated in
Sectional views of different specific embodiments of an electrode 30, 30′, 30″ according to the present invention are illustrated in
In
Sectional views of a micropatterned component 1 according to a specific embodiment of the present invention are represented in
Sectional views of different specific embodiments of an electrode 30, 30′, 30″ according to a specific embodiment of the present invention are represented in
Plan views of different specific embodiments of a set-up of flow channels 33, 33″ of an electrode 30, 30′, 30″ according to the present invention are represented in
Claims
1. A micropatterned component for measuring at least one of an acceleration and a yaw rate, comprising:
- a substrate having a principal plane of extension of the substrate;
- an electrode; and
- a further electrode;
- wherein the electrode has a principal plane of extension of the electrode and the further electrode has a principal plane of extension of the further electrode,
- wherein the principal plane of extension of the electrode is positioned parallelly to a normal direction perpendicular to the principal plane of extension of the substrate,
- wherein the principal plane of extension of the further electrode is set parallel to the normal direction,
- wherein the electrode has an electrode height extending in the normal direction,
- wherein the electrode has a flow channel extending completely through the electrode in a direction parallel to the principal plane of extension of the substrate,
- wherein the flow channel has a channel depth extending parallelly to the normal direction, and
- wherein the channel depth is less than the electrode height.
2. The micropatterned component of claim 1, wherein the channel depth is between 60% and 95% of the electrode height.
3. The micromechanical component of claim 1, wherein the electrode has a principal direction of extension of the electrode, parallel to the principal plane of extension of the electrode and parallel to the principal plane of extension of the substrate, wherein the electrode has several flow channels situated along the principal direction of extension of the electrode, wherein the several flow channels have a channel spacing, and wherein the channel spacing is less than the electrode height.
4. The micromechanical component of claim 1, wherein the electrode has a plurality of partial electrodes spaced apart from one another by the several flow channels, wherein the partial electrodes are situated on a common carrier, wherein the electrode is formed from a functional layer, and wherein the carrier is formed from a further functional layer connected to the functional layer.
5. The micromechanical component of claim 1, wherein the partial electrodes are interconnected in an electrically conductive manner via the carrier, which is connected in an electrically conductive manner to a conducting element via one electrode contact element, wherein the conducting element is situated on the substrate or situated in a further substrate connected to the substrate, and wherein the further substrate includes an integrated circuit.
6. The micromechanical component of claim 1, wherein the electrode is fixed in position relative to the substrate, wherein the further electrode is displaceable relative to the substrate, into a motion along a vibration direction, wherein the vibration direction is set parallel to the principal plane of extension of the substrate, and wherein the vibration direction is set perpendicularly to at least one of the principal plane of extension of the electrode and/or to the principal plane of extension of the further electrode.
7. The micromechanical component of claim 1, wherein the further electrode has the electrode height parallel to the normal direction, wherein the further electrode has a further flow channel extending completely through the further electrode, in parallel with the principal plane of extension of the substrate, wherein the further flow channel has a further channel depth extending parallelly to the normal direction, wherein the further channel depth is less than the electrode height, and wherein the flow channel and the further flow channel are positioned one behind the other in series, or side-by-side in a staggered manner, in a projection direction running along the vibration direction.
8. A method for manufacturing a micropatterned component for measuring at least one of an acceleration and a yaw rate, the method comprising:
- providing, in a first production task, a substrate, which includes a substrate layer having a principal plane of extension of the substrate;
- positioning, in a second production task, a functional layer over the substrate layer in a normal direction perpendicular to the principal plane of extension of the substrate;
- depositing a first patterning mask on the functional layer;
- depositing a second patterning mask on the functional layer, over the first patterning mask, in the normal direction;
- forming, during a first time interval, an electrode and a further electrode from the functional layer as a function of the second patterning mask;
- removing subsequently the second patterning mask;
- forming, in a third production task, during a second time interval subsequent to the first time interval, a flow channel from the electrode as a function of the first patterning mask.
9. The method of claim 8, wherein in the second production task, the electrode and the further electrode are formed from the functional layer as a function of the second patterning mask, so as to have a principal plane of extension of the electrode and a principal plane of extension of the further electrode, respectively, wherein the principal plane of extension of the electrode is set parallel to the normal direction, wherein the principal plane of extension of the further electrode is set parallel to the normal direction, and wherein an electrode height extending in the normal direction is formed at the electrode.
10. The method of claim 8, wherein in the third production task, a flow channel, which extends completely through the electrode in a direction parallel to the principal plane of extension of the substrate and has a channel depth extending parallelly to the normal direction, is formed from the electrode as a function of the first patterning mask, and wherein the channel depth is formed as a function of the second time interval, so as to be less than the electrode height.
11. A method for manufacturing a micropatterned component, for measuring at least one of an acceleration and a yaw rate, the method comprising:
- providing, in a first production task, a substrate which includes a substrate layer having a principal plane of extension of the substrate, the component including a layer construction having the substrate layer, a functional layer and a further functional layer;
- positioning, in a second production task, the further functional layer being positioned over the substrate layer in a normal direction perpendicular to the principal plane of extension of the substrate;
- depositing a patterning mask on the functional layer;
- positioning, in a third production task, the functional layer over the further functional layer in the normal direction;
- forming, in a fourth production task, an electrode and a further electrode from the functional layer and the further functional layer; and
- forming a flow channel has a channel depth extending parallelly to the normal direction from the electrode as a function of the patterning mask.
12. The method of claim 11, wherein in the third production task, the functional layer is provided with a functional layer thickness, and wherein in the fourth production task, the flow channel is formed to have the channel depth equal to the functional layer thickness.
13. The micropatterned component of claim 1, wherein the channel depth is between 70% and 90% of the electrode height.
14. The micropatterned component of claim 1, wherein the channel depth is approximately 80% of the electrode height.
Type: Application
Filed: May 14, 2014
Publication Date: Nov 20, 2014
Patent Grant number: 9229020
Applicant: Robert Bosch GmbH (Stuttgart)
Inventor: Johannes Classen (Reutlingen)
Application Number: 14/120,386
International Classification: G01P 1/00 (20060101); G01P 15/08 (20060101);